The Giant Sea Hare is a very effective algae eater and will clean up hair algae in no time. If it becomes startled, it may release a purple dye to repel attacking fish. In the home aquarium, the Giant Sea Hare will need a good chemical filter system to quickly remove this toxic dye before it causes problems. However this is an extremely rare occurance.
In the wild, it is usually found in shallow areas of seagrasses and coral rubble, preferring the shaded areas. Cover from the lights in the aquarium should be provided. It requires a large area in which to move. It prefers an aquarium with live rock and open sandy areas so that it can graze on algae.
They are sensitive to high levels of copper-based medications and will not tolerate bad water conditions (high nitrates).
If regular feedings of Caulerpa are not possible, it will need a supplemented diet of parboiled lettuce and dried algae.